This invention relates to organic ethers and more particularly to energetic polynitro organic ethers.
Plasticizers which are commonly used in gun propellants and other energetic compositions are nitroglycerin (NG), butanetriol trinitrate (BTTN), metriol trinitrate (METN), and diethylene glycol dinitrate (DEGN). Nitroglycerin and butanetriol trinitrate exhibit relatively low thermal stabilities due to the presence of secondary nitroxy groups. Metriol trinitrate and diethylene glycol dinitrate have relatively low energies. Nitroglycerin and diethylene glycol dinitrate also have the disadvantage of high vapor pressures.
H. G. Adolph and K. Kim in U.S. Pat. No. 4,745,208 issued May 17, 1988, entitled "2,2,2-Trinitroethyl 2-Nitroxyethyl Ether and a Method of Preparation," describe the preparation and properties of 2,2,2-trinitroethyl 2-nitroxyethyl ether (TNEN). They show that the overall properties of 2,2,2-trinitroethyl 2-nitroxyethyl ether in terms of energy, melting point, volatility and thermal stability make it a very desirable energetic plasticizer which can be advantageously substituted for currently used energetic plasticizers such as nitroglycerin, butanetriol trinitrate, metriol trinitrate, and diethylene glycol dinitrate. Their method for preparing 2,2,2-trinitroethyl nitroxyethyl ether (TNEN) is as follows: 2-bromoethanol is reacted with trioxane and aluminum chloride to give chloromethyl 2-bromoethyl ether (39.7%); this material is treated with potassium nitroform in acetone for 48 hours to produce 2,2,2-trinitroethyl 2-bromoethyl ether (30%); stirring this product with silver nitrate in acetonitrile at 45.degree. C. for seven days yields TNEN (36.1%). Disadvantages of their method include: (a) low overall yield of TNEN (less than 5% from 2-bromoethanol); (b) use of potassium nitroform, an unstable explosive intermediate; (c) use of expensive silver nitrate; and (d) long reaction times. Because of these disadvantages, their method is limited to the preparation of small quantities of TNEN. Therefore, a practical, safer, more efficient route to TNEN is needed in order to produce larger quantities of this desirable material.